Field of the Invention
The present disclosure relates to a light conversion film, and a backlight unit and display device having the same, and more particularly, to a light conversion film having superior light conversion efficiency and color characteristics and having a slim shape, and a backlight unit and display device having the same.
Discussion of the Related Art
Liquid Crystal Displays (LCDs) have low power consumption, good portability, technology compactness, and high added-value. In particular, LCDs are non-emissive type devices and thus do not form an image by itself. Also, because LEDs must receive light incident from the outside to form an image, a light source for providing light is required.
In addition, Cathode Fluorescent Lamps (CCFLs) have been mainly used as light sources in the past. However, CCFLs have a difficulty in securing of brightness uniformity and are deteriorated in color purity if the CCFLs are manufactured in large scale.
Thus, three-color light emitting diodes (LEDs) instead of the CCFLs are being used in recent years as light sources. When three-color LEDs are used, a high color purity can be used to form high-quality images. However, because three-color LEDs are expensive, the manufacturing costs increase. As a result, blue LEDs that are relatively inexpensive are being used as light sources. For this, the blue light is converted into red light and green light using a light conversion film including red quantum dots and green quantum dots. White light can also be produced.
In particular, light emitted from a corresponding blue LED is excited by the red quantum dot and green quantum dot within the light conversion member and thus is converted into red light and green light. Here, blue light that is not excited by the quantum dots can be mixed with the red light and green light to produce white light.
In addition, the light conversion member can be manufactured in a tube shape and disposed on a side surface of a light source unit. However, in this instance, the density of light incident into the quantum dots may increase causing the quantum dot to degrade. Thus, quantum dots can be dispersed into a matrix resin and then cured to prepare a light conversion member in the form of a film.
The light conversion member can then be disposed on a light guide plate. In this instance, because light incident from a light source is low in density, the degradation of the quantum dots can be reduced. However, an amount of quantum dots used for realizing white light increases. Particularly, an amount of green quantum dots increases.
In more detail, green light excited from the green quantum dots is excited again by the red quantum dots and thus converted into red light. Thus, to uniformly maintain rates of the green and red lights generated in the light conversion member, an amount of green quantum dots within the light conversion member is relatively larger than that of red quantum dots. In general, the amount of green quantum dots is about ten times greater than that of red quantum dots in the related art light conversion film.
In addition, when the amount of quantum dots within the film increases, a distance between the quantum dots decreases, which causes reabsorption of the quantum dots, thereby deteriorating the light emitting efficiency. To maintain the distance between the quantum dots, the film has an increased thickness. However, if the film thickness increases, an amount of light absorbed by the matrix resin increases, which deteriorates the light efficiency. In addition, the energy needed for curing the matrix resin increases in both process time and cost. Also, when the film is formed, the matrix resin may not be completely cured or is deteriorated in adhesion and/or physical property.